1. Field of the Invention
The present invention relates to a computer system for ordering parts necessary for production according to a production plan. The present invention especially relates to a computer system for rapidly processing, when a production plan requiring various parts is changed, order of parts according to the changed production plan such that the parts already ordered according to the production plan before the change are used in the changed production plan.
2. Description of the Related Art
In a system for ordering parts necessary for production according to a production plan, ordering parts is performed by a form of separation delivery that parts ordered at once are divisionally delivered on a plurality of delivery times in order to control the stock volume of the parts for production in the factory in a desirable range of volume. Time which is moved for delivery is called a lead time for delivery.
Japanese patent No. 3680264 discloses a system for ordering parts according to the progress of production. Japanese patent Application Laid-Open No. 2002-333915 discloses the ordering parts or the instructions for delivery is performed at different timing.
No matter how the order and the delivery are managed so as to control the stock volume by the manufacturer which uses the parts in a desirable range of volume as shown above, when a model for which parts has been already ordered is substantially changed to other model according to specification change or design change etc., it happens that parts for the other model need to be ordered immediately.
In this case, it needs work to control or dispose the parts already ordered for the previous model before the model change. It is efficient that common parts usable for new production in the parts already ordered are directly applied to the new production. However, in production for product such as automobile, which needs plenty of parts over one thousand to tens of thousands, it needs complicated and laborious work to specify common parts usable for the new production, confirm the quantity of the parts and set timing for order/delivery when ordering parts necessary for the new production.